U.S. Pat. No. 4,023,310 issued May 17, 1977, to John W. Lovely and Robert N. Hobbs discloses a grinding machine having a wheel dresser with a diamond dresser carried on a pivotal holder arm. The pivotal holder arm is pivotable about a substantially vertical axis to cause the diamond dresser to be moved in a circular arc path against the grinding wheel to dress a circular arc on the working face of the wheel. The diamond dresser is manually adjustable in position on the holder arm to vary the radius of the circular arc path traced by the dresser and thus the radius of the working surface dressed on the wheel.
U.S. Pat. No. 4,603,677 issued Aug. 5, 1986, to Richard H. Gile and Edward C. Bourgoine describes a wheel dresser for effecting orthogonal dressing of a grinding wheel by a diamond dresser. The diamond dresser is mounted on a pivotal holder similar to that of U.S. Pat. No. 4,023,310. Coarse adjustment of the diamond dresser relative to the pivot line or axis of the holder is effected manually by a set screw that slides a dresser support plate relative to the pivotal holder. Fine adjustment of the diamond dresser relative to the pivot line is provided by a manually turned threaded adjustment screw that deflects a plate carrying the diamond dresser. In this way, the radius of the circular arc path of the dresser can be varied.
U.S. Pat. No. 4,103,668 issued Aug. 1, 1978, to Hiedeo Nishimura et al discloses a rotary dresser wheel carried on a compound slide assembly controlled by an electronic control unit.
U.S. Pat. No. 4,274,231 issued June 23, 1981, to James Verega illustrates one or more dresser wheels that move along two different axes relative to the grinding wheel under control of the same automatic CNC unit which controls movement of the grinding wheel and table during grinding operations.